"Away We Go" seems like a movie out of time, which is not the same thing as timeless. With few alterations it could pass for a movie from the early 1970s. A road-trip odyssey, it fobs off nonconformity as a spiritual virtue. It's a hippie movie for the 21st century.

The problem, is, the best hippie movies – like, say "Alice's Restaurant" – were not as relentlessly engineered as "Away We Go," which was written by husband-and-wife alt-lit icons Dave Eggers and Vendela Vida. Sam Mendes, who directed, is renowned for such hypercontrolled, diagrammatic movies as "American Beauty" and "Revolutionary Road." His work here is much more wayward and (seemingly) improvisatory than usual, but finally the film is a species of screed. Instead of taking it out on the soulless suburbs, as in those other two films, Mendes is indicting just about everywhere else. High or low, urban or the sticks, anomie is still anomie.

John Krasinski and Maya Rudolph play Burt and Verona, a rural Colorado couple expecting their first child. When his parents (played, risibly, by Jeff Daniels and Catherine O'Hara) unexpectedly announce that they are moving to Belgium, Burt and Verona decide to hit the road in search of a better place to live and bring up their baby. (Conveniently, both are freelancers – he sells insurance over the phone, she's a medical illustrator – with no need for a permanent address. In hippie movies, income is never a big issue.)

Gawky, hirsute Burt is meant to be lovably childlike but he seemed kind of stunted to me. (Krasinski is miscast.) Verona is far more level-headed, at least compared with him. Their first stop is Phoenix, where they hook up with a former co-worker of Verona's, Lily (Allison Janney), and her husband (Jim Gaffigan). Two more obnoxious individuals you will search far and wide to find. Janney is remarkable in the role, but Lily's hysterical high spirits are an indictment. They personify the soullessness of hickdom.

In Tucson, the couple meet up briefly with Verona's remarkably sane sister (Carmen Ejogo) – how did Tuscon escape the scourge? – before moving on to Madison, Wis. Burt's childhood friend Ellen (a pitch-perfect Maggie Gyllenhaal) is a Women's Studies professor who now calls herself LN; her common-law husband Roderick (Josh Hamilton), a liberated guy, loves male sea horses because they carry babies in their brood pouches. LN and Roderick allow their little son to share their bed. Did I say "Away We Go" is a neohippie movie? It is, but of a special sort. The filmmakers serve up a poisonous portrait of these superannuated hippies in order to establish Burt and Verona as the real deal.

The Montreal segment, where Burt and Verona indulge in melancholy good times with a married pair of former college classmates (well played by Chris Messina and Melanie Lynskey), and their rainbow coalition of adopted kids, appears to be in the movie for its own sweet sake. That's why I liked it. (I also like the fact that nothing in the movie is made of Burt and Verona's mixed-race partnership.) I realize Mendes probably intended the Montreal sequence as a cautionary tale for his two parents-to-be, but that's not how it comes across. It's too full of the juices of real life for that.

In the end, "Away We Go" is highly sentimental (as hippie movies invariably are). It's about finding a place to belong in a world that doesn't make it easy, and it's also about the almost hallucinatory anxiety of becoming a parent. Good subjects, weak payoff.

The film's one extraordinary aspect, which makes it well worth seeing despite its carefully coiffed shagginess, is Maya Rudolph's performance. For those who only know her from her comic sketches on "Saturday Night Live," her work here will come as a revelation (although her brief but marvelous work in Robert Altman's "A Prairie Home Companion," where she really was pregnant, should have been a tip-off). She has an emotional honesty here that most performers never achieve in a lifetime. She's a major actress. Now she needs a major movie. Grade: B- (Rated R for language and some sexual content.)